At the beginning of this level, there's a turtle looking island. Rather than getting off the island, directly above the starting location there's a shiny spot that makes lums appear. Try to collect them all.
The first pattern is there's a line going right to left, then another going left to right. Try to get these as fast as possible, you should only need a normal jump, and some floating.
Then there's a two lines of lums coming from top to bottom, doing a u turn and going up. Get under the right most and ground pound (jump, and then hit down and attack) and clear the first, then go to the second line and do the same.
Finally there's a third line going left to right, a little higher than expected, either ground pound and glide to collect them or run over and collect them.
If you get all five lines of lums, this achievement unlocks almost immediately after the last lum is picked up,